I used to buy F91W watches all the time. they were fun and practical, but wasteful.
the most shameful fact about the F91W isnt its spartan design or its affordable price, but the fact that the timepiece with its ten year battery will easily outlast its resin strap, and its springbars are nothing more than pot steel held into the soft plastic lugs by friction alone. Chances are, when you replace the band after a few years youll pay just as much as the watch to do so, and run a pretty good risk of damaging the springbars to the point of rendering them warped or broken. the simple act of removing the springbars themselves is enough to strip out the lugs sometimes.
the clearances between the lugs and springbars are also very tight, so it discourages aftermarket additions like NATO bands or third party straps.
This is hilarious, I realized the exact same thing about the F-91w after wearing them for 3 or 4 years. Another alternative is the Casio F-84w, which is almost completely identical to the F-91w. It's slightly more expensive, but the default strap has small circular rather than wide ovular notches. This seems to have completely fixed the strap weakening/breaking problem. I have only had it for about a year, but it shows no signs of letting up anytime soon.
There's been a real dip in strap quality. I remember the only thing that would kill one was complete destruction(crushing) or simply losing it.
Ones I've purchased in past 5~ years all have had straps fail. They've clearly switched to cheaper materials.
They made a new model 'W-217H', which is just a larger F91W. I enjoyed the larger face and wouldn't go back to a F91. But the strap too broke a few months after use.
And like you said, with the cheapest of straps being almost the cost of the watch, and there's no guarantee it'll easily fit.
the most shameful fact about the F91W isnt its spartan design or its affordable price, but the fact that the timepiece with its ten year battery will easily outlast its resin strap, and its springbars are nothing more than pot steel held into the soft plastic lugs by friction alone. Chances are, when you replace the band after a few years youll pay just as much as the watch to do so, and run a pretty good risk of damaging the springbars to the point of rendering them warped or broken. the simple act of removing the springbars themselves is enough to strip out the lugs sometimes.
the clearances between the lugs and springbars are also very tight, so it discourages aftermarket additions like NATO bands or third party straps.
the B650WB is somewhat more durable.